Extended Data Figure 3. Mitochondrial hyperfusion regulates the accumulation of mtDNA nucleoid stress in TF^D MEFs.

a-b, WT MEFs were transfected with control or TFAM siRNAs for 96hrs. Cells were fixed and processed for EM analysis (a). Mitochondrial perimeter measurements were obtained from multiple independent images, stratified into groups, and graphed as percentage of the total number of mitochondria counted for each sample (b). c-e, WT MEFs were transfected with control, Mfn1, and/or TFAM siRNAs for 96hrs. Cells were fixed and stained with anti-Hsp60 antibody [Mito] and anti-DNA antibody [DNA] for confocal microscopy (c). Nucleoid area from multiple independent images was calculated as previously described (d). RNA was extracted for ISG expression analysis by qRT-PCR (e). f, WT and Tfam+/− MEFs were transfected with the indicated siRNAs for 96 hours and ISG expression analyzed by qRT-PCR. Error bars indicate ± s.e.m. of triplicates and data are representative of two independent experiments. **=p<0.01, ***=p<0.001.